Studies are being performed to obtain an estimate of the structural variety of complex carbohydrates synthesized by a single mammalian cell type in culture. Variants of this cell line with alterations in membrane carbohydrates due to in vivo defective glycosyltransferase activities are examined for involvement of the same defects in biosynthesis of carbohydrates on non-membrane glycoproteins. In addition, the specific involvement of cell surface oligosaccharides in Sindbis virus adsorption is also being explored.